1. Field of the Invention
This invention relates to a runner for mounting on a roll gap sled for measuring the misalignment of rolls in a machine for continuously casting a metal slab.
2. Prior Art
It is known to provide a sled-type apparatus for passing through the opposed rolls of a continuous caster in order to measure the gap between each pair of opposed rolls. Such a sled is fitted with transducers which measure the magnitude of the gap between opposed pairs of caster segment rolls. The length of the sled is less than the spacing of three rolls in the casting direction. This measurement value is assigned to the pair of rolls for which the measurement is made and is called the "roll gap" or simply the "gap" between the rolls so measured.
Roll gap has a direct effect on product quality and an incorrect roll gap contributes to slab casting defects such as core cracking. By measuring roll gap, it is possible to detect failed bearings and other problems in a caster segment by thus detecting a roll gap value which is larger than that called for in the caster design.
Traditional roll gap sleds cannot detect and measure roll segment alignment, i.e. a segment-by-segment transition of the slab passline. It also is necessary that the segment-to-segment transition, or alignment, be held within specified tolerances to allow for the production of a high quality, defect-free slab.